Neuropsychiatric abnormalities are among the most frequent early symptoms in AIDS. Some of these symptoms have been suggested to reflect effects of the CNS virus infection upon major monoamine neurotransmitter systems. Measurements of CSF monoamines and their metabolites and precursors before and after chemotherapy may help elucidate the basis of neuropsychiatric symptoms. As part of a collaborative study with the NCI (Pediatric Branch, Dr. Pim Brouwers) we have examined baseline cerebrospinal fluid (CSF) samples from over 50 children with HIV infection to evaluate possible changes in CSF tryptophan, dopamine, HVA and other monoamine metabolites previously reported in adults with HIV infection. Analysis of the neurochemical data for possible associations with clinical state, including full scale IQ tests and other evidence of CNS functional changes is underway. Because only a small amount of normative data on CSF monoamine metabolites are available for young children, we are collaborating with investigators at Washington University in a pilot study of 'leftover' CSF from over 100 children. As part of another collaborative project established with the NCI (Laboratory of Biochemistry, Dr. Dean Hamer and colleagues), we have been enrolling female and male subjects and collecting data including demographic information, personality inventories and DNA samples to investigate the contribution of multigenic factors to individual variations in personality. Genetically-based contributions of about 40% of the variance in personality characteristics within the normal range of human behaviors have been demonstrated in twin studies. Some personality characteristics are thought to influence risk-taking, sensation-seeking and other features that might contribute to drug abuse or other behaviors that could increase risks for HIV infection. Our studies of possible associations between genes that affect CNS functions and human personality are broad-ranging, but because approximately one- half of the population sample that we are studying in ongoing collaborations with Dr. Hamer includes homosexual males and females, a portion of the costs of this study is being requested as AIDS-related funds.